1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device and a method for fabricating the same, which can prevent a signal loss in an integrated circuit that processes radio frequency signals.
2. Discussion of the Related Art
As the silicon (Si) semiconductor fabrication technology develops, an operation frequency of integrated circuits has been gradually increasing close to the radio frequency range. If the operation frequency of a device or circuit having a silicon substrate is higher than 2 GHz, there is a signal loss along interconnections. To overcome this problem, a semiconductor material, GaAs, which exhibits a semi-insulating property, has been used instead of a Si substrate. The use of GaAs allows signal transmission up to 10 GHz in the circuit without signal loss and without having to match the impedance characteristic. However, in the case of transmitting of a signal with the operation frequency greater than 10 GHz using a GaAs substrate, a process, such as an electrolytic plating, is needed to match the impedance characteristic of a transmission line.
The above-described conventional semiconductor device has the following problems. The background technology of using a GaAs substrate for preventing the signal loss in a radio frequency processing integrated circuit is not applicable to a Si substrate.
Accordingly, the present invention is directed to a semiconductor device and a method for fabricating the same that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a semiconductor device and a method for fabricating the same which can prevent a signal loss in an integrated circuit processing radio frequency signals.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purposes of the present invention, as embodied and broadly described, the semiconductor device includes a first insulating film formed on a substrate and having a plurality of holes therein; a cavity formed under the first insulating film; an impurity region formed in the substrate and around the cavity; a second insulating film formed on portions of the first insulating film to fill the holes and a space between the cavity and the impurity region; a plurality of contact holes formed to expose certain portions of the impurity region; and a plurality of wiring layers formed to be in contact with the impurity region through the contact holes.
In another aspect of the present invention, there is provided a method for fabricating a semiconductor device including the steps of forming a first insulating film on a substrate to define a plurality of holes therein; forming a cavity under the first insulating film; forming an impurity region in the substrate and around the cavity; forming a second insulating film on portions of the first insulating film to fill the holes and a space between the cavity and the impurity region; forming a plurality of contact holes to expose certain portions of the impurity region; and forming a plurality of wiring layers in contact with the impurity region through the contact holes.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.